First Look: Mossberg Reserve Series O/U Shotguns If you asked the hard-core upland hunters which is their favorite type of shotgun to carry in the woods, I’d go out on a limb and say the majority will answer an over/under in either 20 or 28-gauge. Now some may prefer 410 bore, or a 12-gauge, while others are more comfortable with a double barrel side-by-side, but that’s a whole other can of worms for another article – anyway I digress. The main reason over/under shotguns are so popular in the upland hunting community is the ability to customize their shot type and spread to pair with different types of wing shooting. Also, their reliability in the field is next to none. If you’re looking for that new grouse duster for 2021, the Mossberg Reserve Series will likely have something that catches your eye and fits the bill!